/*
 * Copyright (C) 2011 Nicola Bonzanni
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package nl.vu.few.ibivu.jlemon;

import nl.vu.few.ibivu.jlemon.concepts.Arc;
import nl.vu.few.ibivu.jlemon.concepts.Edge;
import nl.vu.few.ibivu.jlemon.concepts.HasEdges;
import nl.vu.few.ibivu.jlemon.concepts.HasEdge;
import nl.vu.few.ibivu.jlemon.concepts.Node;

public abstract class AbstractGraph<N extends Node & Comparable<N>, E extends Edge & Comparable<E>, A extends Arc & HasEdge<E> & Comparable<A>>
		extends AbstractDigraph<N, A> implements HasEdges<N, E, A> {

	@Override
	public A direct(E edge, N node) {
		return direct(edge, u(edge).equals(node));
	}

	@Override
	public A oppositeArc(A arc) {
		return direct(arc.edge(), !direction(arc));
	}

	@Override
	public N oppositeNode(N node, E edge) {
		if (node.equals(u(edge)))
			return v(edge);
		else if (node.equals(v(edge)))
			return u(edge);
		else
			// TODO Throw an exception?
			return null;
	}
}
